1. Field of the Invention
The present invention relates to an evaluation method of a light-emitting element material. In particular, the present invention relates to an evaluation method for distinguishing a function of a light-emitting element material. In addition, the present invention relates to a light-emitting element having a material to which the evaluation method is applied.
2. Description of the Related Art
In a light-emitting element in which light is emitted by current flowing between electrodes due to hopping of carriers between energy levels, an operation characteristic is greatly affected by an oxidation-reduction potential, electrochemical stability, and the like of a material. Therefore, in the development of a light-emitting element material, an oxidation-reduction potential, electrochemical stability, and the like are examined by cyclic voltammetry measurement and whether the manufactured material is suitable for a light-emitting element material or not is evaluated (For example, Patent Document 1).
However, there is a case where reliability of a light-emitting element, especially reliability of a life-time thereof, is unfavorable even when the element is manufactured by using a material which is distinguished to be suitable based on the data of an oxidation-reduction potential, electrochemical stability, and the like.
[Patent Document 1]
Japanese Patent Application Laid-Open No. 2004-277377 (Embodiment 2)